21013220131221 has 8 divisors (see below), whose sum is σ = 28020180209760. Its totient is φ = 14007536736752.

The previous prime is 21013220131219. The next prime is 21013220131223. The reversal of 21013220131221 is 12213102231012.

It is an interprime number because it is at equal distance from previous prime (21013220131219) and next prime (21013220131223).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21013220131221 - 2¹ = 21013220131219 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21013220131223) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 319132611 + ... + 319198448.

It is an arithmetic number, because the mean of its divisors is an integer number (3502522526220).

Almost surely, 2^{21013220131221} is an apocalyptic number.

It is an amenable number.

21013220131221 is a deficient number, since it is larger than the sum of its proper divisors (7006960078539).

21013220131221 is a wasteful number, since it uses less digits than its factorization.

21013220131221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 638342035.

The product of its (nonzero) digits is 288, while the sum is 21.

Adding to 21013220131221 its reverse (12213102231012), we get a palindrome (33226322362233).

The spelling of 21013220131221 in words is "twenty-one trillion, thirteen billion, two hundred twenty million, one hundred thirty-one thousand, two hundred twenty-one".